Pump unit consisting of pressure oil pump and oil reservoir, especially for servo-steering systems

ABSTRACT

A pump unit consisting of an oil pump space and of an oil reservoir space, especially for servo-steering systems, in which a partition wall formed in one piece with the casting of the housing separates the pump space from the reservoir space; the housing opening of the reservoir space disposed at one housing in the direction of a reference axis extends over the entire housing cross section perpendicular to the reference axis while the housing wall portions of the reservoir space extending along the reference axis, are disposed parallel to the reference axis or in such a manner relative to the reference axis that its wall sections disposed nearer to the housing opening do not have a smaller spacing from the reference axis than directly adjacent wall sections which are disposed further away from the housing opening.

United States Patent [19 Furster et al.

PUMP UNIT CONSISTING OF PRESSURE OIL PUMP AND OIL- RESERVOIR, ESPECIALLY FOR SERVO-STEERING SYSTEMS [58] Field Filed:

Appl.

Peter Eisen, both of Stuttgart, Germany Daimler-Benz Aktiengesellschaft, Stuttgart-Untertuerkheim, Germany Sept. 22, 1971 US. Cl. ..4l5/2l9 Int. Cl ..F0ld 25/24 of Search ..4l5/2l9 C, 170 A, 112, 111, 4l5/2l9 References Cited UNITED STATES PATENTS 4/1920 Standerwick ..4 l 5/] l2 4/1946 Gilbert, Sr. ..4l5/l70 A 6/1947 Gilbert, Sr. ..4l5/l70 A Chubbuck ..4l5/l70 A Montgomery et al. ..4l5/l70 A Primary Examiner-Henry F. Raduazo [57] ABSTRACT A pump unit consisting of an oil pump space and of an oil reservoir space, especially for servo-steering systems, in which a partition wall formed in one piece with the casting of the housing separates the pump space from the reservoir space; the housing opening of the reservoir space disposed at one housing in the direction of a reference axis extends over the entire housing cross section perpendicular to the reference axis while the housing wall portions of the reservoir space extending along the reference axis, are disposed parallel to the reference axis or in such a manner relative to the reference axis that its wall sections disposed nearer to the housing opening do not have a smaller spacing from the reference axis than directly adjacent wall sections which are disposed further away from the housing opening.

11 Claims, 3 Drawing Figures PATENTEUHAR 1 31m FIG. 2

R rt l H c A 0 J s N A .H

PETER EISEN ATTORNEYS PUMP UNIT CONSISTING OF PRESSURE OIL PUMP AND OIL RESERVOIR, ESPECIALLY FOR SERVO-STEERING SYSTEMS separates the pump space from the reservoir space, as

described in Ser. No. 137,775, filed Apr. 27, 1971 having common assignment.

The aim underlying the present invention resides in constructing such a pump unit favorably as regards its structural configuration and manufacture. For that purpose provision is made according to the present invention that the housing opening of the reservoir space disposed at one housing end in the direction of a reference axis, extends over the entire housing cross section disposed perpendicularly to the reference axis, and in that the housing wall portions of the reservoir space extending in the direction of the reference axis, extend exclusively parallel to the reference axis or in such a manner relative to the reference axis that wall sections disposed nearer to the housing opening do not exhibit a smaller distance to the reference axis than the wall sections directly adjacent thereto and disposed further removed from the housing opening.

As a result of the construction according to the present invention, the reservoir space is free of enlargements in the projection of the housing opening so that the housing walls can not have any undercuts. A simple core for the reservoir space results therefrom.

According to a further feature of the pump unit of the present invention, provision is made that the partition wall is devoid of any undercuts in the direction of the reference axisfrom the housing opening of the reservoir space toward the opposite housing end. It is possible thereby to make the cast housing completely by the die-casting process.

If the arrangement is made according to a further feature of the present invention in such a manner that the pump space-is located at the housing end opposite the housing opening of the reservoir space, then the housing wall of the pump space may pass over into the housing wall of the reservoir space in such a manner that the essentially cylindrical partition wall includes a circular arc of maximum 180 whereby undercuts are avoidable in a simple manner.

A considerable reinforcement and compact construction of the pump unit according to the present invention is achieved in that the pump space is arranged in a housing comer formed by a longitudinal wall of the housing extending essentially in the direction of the reference axis and by the housing end wall extending essentially transversely to the reference axis, As a result thereof, the angle subtended by the partition wall becomes small, and it is thereby made easier to construct the partition wall without undercuts.

According to a further feature of the invention, provision is made that the cast housing is provided with fastening lugs within the area of its housing corner for the pump space. The mounting lugs are thereby ar ranged in a particularly rigid area of the housing casting whereby the rigidity of this housing area is further increased by the wall webs of the mounting eyes or lugs.

Accordingly, it is an object of the present invention to provide a pump unit consisting of pressure oil pump and oil reservoir, especially for servo-steering systems, which avoids by simple means the aforementioned shortcomings and drawbacks encountered in the prior art.

Another object of the present invention resides in a pump unit which avoids far-reachingly any undercuts in the housing walls thereof, thereby facilitating manufacture.

A further object of the present invention resides in a pump unit consisting of oil pump space and of oil reservoir space, separated by a partition wall, in which a simple core can be used in the casting operation for the reservoir space. *1

Still a further object of the present invention resides in an integrally cast pump unit of the type described above which can be made completely as a one piece die-casting.

Another object of the present invention resides in a pump unit consisting of oil pump space and oil reservoir space which is particularly simple in construction yet offers advantages as regards strength and rigidity, particularly within the areas where the unit is mounted at other parts of an engine.

These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein FIG. 1 is an axial cross sectional view containing the reference axis through a housing casting according to the present invention,

FIG. 2 is a cross sectional view taken along line lI-II through the housing casting of FIG. 1, and

FIG. 3 is an elevational view of the housing casting taken in the direction of arrow III of FIG. 2.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, the cast housing generally .designated by reference numeral 10 is subdivided by an essentially cylindrically extending partition wall generally designated by reference numeral 11 into an oil reservoir space 12 and a pump space 13. The reservoir space 12 is provided at one housing end generally designated by reference numeral 14 with a housing opening 15 that opens up the entire inner cross section of the reservoir space 12. The housing wall 16 of the reservoir space 12 is cylindrical, and the associated cylinder axis coincides with a reference axis 17 so that the wall sections disposed closer to the housing opening 15 have the same distance to the reference axis 17 as the adjacent wall sections 16b disposed farther away from the housing opening 15. In this manner undercuts in the housing wall with respect to the projection of the housing opening 15 are avoided so that the core for the reservoir space 12 can be removed after the casting operation without destruction. For the same reason also the partition wall 11 is free of undercuts with respect to the projection of the housing opening 15. This is achieved in the first instance in that the pump space 13 is arranged directly at the housing end generally designated by reference numeral 18 and disposed opposite the housing opening 15. The partition wall 11 thereby includes a wall section 19 extending parallel to the reference axis 17, which passes over at one end into the housing end wall 20 extending transversely to the reference axis 17 and at the other end into a cylindrical wall section 21 which includes an angle 22 of less than 180 and passes over into the housing wall 16. By reason of the location of the pump space 13 near the housing end, the angle 22 (FIG. 1) of the cylindrical wall section 21 can be kept equal to or smaller than 180 so that the partition wall 11 does not form any undercuts with respect to the projection of the housing opening 15.

The axis 23 (FIG. 2) of the cylindrical pump space 13 is offset with respect to the reference axis 17 in the direction toward a housing corner generally designated by reference numeral 24 which is formed by the imaginery extensions 25 and 26 of the housing end wall 20 and the housing longitudinal wall 16. The angle 22 of the cylindrical wall section 21 becomes thereby particularly small, which is desirable for a construction of the partition wall free of undercuts, and the cast housing becomes particularly strong and rigid within the area of the corner 24.

As can be seen from FIG. 3, wall webs 28, 2 and 30 with mounting eyes 31, 32 and 33 are provided at the wall portions 27 of the pump space 13 which are particularly rigid by reason of their location close to the corner. The rigidity of this mounting arrangement is very high, especially as the wall webs 28 to 30 further increase the rigidity of the pump housing area.

While we have shown and described only one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as are known to those skilled in the art and we, therefore, do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

What we claim is:

1. A pump unit including a pressure oil pump and an oil reservoir, in which a partition wall means formed in one piece with a common, cast housing means separates the pump space from the reservoir space, characterized in that the reservoir space is provided with a housing opening, disposed in the direction of a reference axis at one housing end, which extends substantially over the entire housing cross section disposed perpendicularly to the reference axis, and in that the housing means includes housing wall portions of the reservoir space extending generally in the direction of the reference axis in such a manner relative to the reference axis that the sections of said wall portions disposed nearer the housing opening do not have a smaller spacing relative to the reference axis than the directly adjacent wall sections disposed more remote from the housing opening.

2. A pump unit according to claim 1, characterized in that said housing wall portions extend exclusively substantially parallel to the reference axis.

3. A pump unit according to claim 1, characterized in that the pump unit is part of a servo-steering system.

4. A pump unit according to claim 1, characterized in that the partition wall means is substantially devoid of undercuts in the direction of the reference axis from the housing opening toward the o ppsite housing end.

5. A pump unit according to c arm 4, characterized in that the pump space is disposed at the housing end opposite the housing opening of the reservoir space.

6. A pump unit according to claim 5, characterized in that the pump space is arranged within the area of a housing corner formed by imaginary extensions of housing wall portions extending essentially in the direction of the reference axis and of a housing end wall extending essentially transversely to the reference axis.

7. A pump unit according to claim 6, characterized in that the cast housing means is provided within the area of its housing corner for the pump space with mounting lug means.

8. A pump unit according to claim 7, characterized in that said housing wall portions extend exclusively substantially parallel to the reference axis.

9. A pump unit according to claim 1, characterized in that the pump space is disposed at the housing end opposite the housing opening of the reservoir space.

10. A pump unit according to claim 1, characterized in that the pump space is arranged within the area of a housing corner formed by imaginary extensions of housing wall portions extending essentially in the direction of the reference axis and of a housing end wall extending essentially transversely to the reference axis.

11. A pump unit according to claim 10, characterized in that the cast housing means is provided within the area of its housing corner for the pump space with mounting lug means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CUR EC'IIUN 3, 720, 47s Dated March 13, 1973 Patent No.

Hans-Joachim M. Forster and Peter Eisen Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

TITLE PAGE the line which now reads:

"Furster et 1 45-] lVIarch 13, 1973" should read as follows:

"Forster et al 451 March 13, .1973

the line which now reads:

,"[75] Inventors: Hans-Joachim Furster; Peter" should read as follows:

- [75] Inventors: Hans-Joachim M. Forster; Peter The following should be added to the TITLE PA GE:

- Foreign Application Priority Data September 24, 1970 Germany P 2047 040.0

Signed end sealed this 20th day of November 1973.

(SEAL) Attest:

EDWARD M.FLE'I'CHER,JRo RENE D. TEGI'MEYER Acting Commissioner of Patents Attesting Officer USCOMM OC 60376-F 69 h u.s. oovumucul Pmuvmo onlci nu o-aso-Jn F ORM PO-1 050 (10-69) 

1. A pump unit including a pressure oil pump and an oil reservoir, in which a partition wall means formed in one piece with a common, cast housing means separates the pump space from the reservoir space, characterized in that the reservoir space is provided with a housing opening, disposed in the direction of a reference axis at one housing end, which extends substantially over the entire housing cross section disposed perpendicularly to the reference axis, and in that the housing means includes housing wall portions of the reservoir space extending generally in the direction of the reference axis in such a manner relative to the reference axis that the sections of said wall portions disposed nearer the housing opening do not have a smaller spacing relative to the reference axis than the directly adjacent wall sections disposed more remote from the housing opening.
 1. A pump unit including a pressure oil pump and an oil reservoir, in which a partition wall means formed in one piece with a common, cast housing means separates the pump space from the reservoir space, characterized in that the reservoir space is provided with a housing opening, disposed in the direction of a reference axis at one housing end, which extends substantially over the entire housing cross section disposed perpendicularly to the reference axis, and in that the housing means includes housing wall portions of the reservoir space extending generally in the direction of the reference axis in such a manner relative to the reference axis that the sections of said wall portions disposed nearer the housing opening do not have a smaller spacing relative to the reference axis than the directly adjacent wall sections disposed more remote from the housing opening.
 2. A pump unit according to claim 1, characterized in that said housing wall portions extend exclusively substantially parallel to the reference axis.
 3. A pump unit according to claim 1, characterized in that the pump unit is part of a servo-steering system.
 4. A pump unit according to claim 1, characterized in that the partition wall means is substantially devoid of undercuts in the direction of the reference axis from the housing opening toward the opposite housing end.
 5. A pump unit according to claim 4, characterized in that the pump space is disposed at the housing end opposite the housing opening of the reservoir space.
 6. A pump unit according to claim 5, characterized in that the pump space is arranged within the area of a housing corner formed by imaginary extensions of housing wall portions extending essentially in the direction of the reference axis and of a housing end wall extending essentially transversely to the reference axis.
 7. A pump unit according to claim 6, characterized in that the cast housing means is provided within the area of its housing corner foR the pump space with mounting lug means.
 8. A pump unit according to claim 7, characterized in that said housing wall portions extend exclusively substantially parallel to the reference axis.
 9. A pump unit according to claim 1, characterized in that the pump space is disposed at the housing end opposite the housing opening of the reservoir space.
 10. A pump unit according to claim 1, characterized in that the pump space is arranged within the area of a housing corner formed by imaginary extensions of housing wall portions extending essentially in the direction of the reference axis and of a housing end wall extending essentially transversely to the reference axis. 